[ATM] Mirror Diagonal/Optical Flat

[Jeff Baldwin]

If you space them well with the right material you won't scratch them. I use 
a method told on this group by somebody, forgot who, sorry, when you use 
small triangular pieces of cellophane from CDs or cigarette boxes. To get 
the right number of fringes you gently slide the cellophane out a bit. Less 
material squishes a bit more, and it lowers very slightly, changing the 
number of fringes. No scrathes. Also easy to separate, again, no scratches. 
I also like to support the lower glass directly under the cellophane pieces. 
If the glasses bend, at least this will allow them to bend somewhat 
uniformly and not introduce onfusion, at least if the glasses are the same 
size, thickness and weight.
JB

Jeff and Glenda Baldwin
Lathrop, CA
www.agetawaylogcabin.com
www.stocktonastro.org



> By the way, has anyone tried using oil, rather than air, in the gap 
> between
> the two flats?  It seems that one should be able to find a lubricant
> (mineral oil?) with a suitable index of refraction, thus helping to avoid
> scratches.
>
> Ted.